1. Field of the Invention
The present invention relates to a nitride semiconductor light-emitting device and a method for producing the same.
2. Description of the Background Art
Conventionally, a nitride semiconductor light-emitting device usable for a light-emitting diode or the like is known. In such a nitride semiconductor light-emitting device, when a voltage is applied, an electron and a hole are recombined in an active layer, and as a result, light is generated. The active layer may have a single quantum well structure, or may have a multiple quantum well structure as described in Japanese Patent Laying-Open No. 2005-109425 and Japanese Patent Laying-Open No. 2000-349337, for example.
Japanese Patent Laying-Open No. 2005-109425 describes that an active layer is formed by sequentially stacking a non-doped InGaN quantum well layer and a GaN barrier layer doped with an n-type impurity. This publication also describes that the GaN barrier layer doped with an n-type impurity has a diffusion preventive film at the interface where the GaN barrier layer is in contact with the aforementioned InGaN quantum well layer, and that the diffusion preventive film contains an n-type impurity at a concentration lower than that in the GaN barrier layer.
Japanese Patent Laying-Open No. 2000-349337 describes that an active layer contains an n-type impurity, and that concentration of the n-type impurity in the active layer is higher in the n layer side than in the p layer side.
Recently, as use application of a nitride semiconductor light-emitting device, a backlight for liquid crystal and an electric bulb for illumination are considered, and the case where a nitride semiconductor light-emitting device is driven at a large current is on the increase.